Amenorrhea is the absence or suppression of menstruation in females. Excessive training in females can sometimes lead to this. Excessive training combined with restricted eating leading to amenorrhea (for 3 to 6 consecutive cycles) and osteoporosis is sometimes considered a syndrome referred to as the female athlete triad.

Amenorrhea is normal before puberty, after menopause, and during pregnancy and lactation.

The most common causes of (abnormal) amenorrhea are congenital abnormalities in the reproductive tract and metabolic disorders such as obesity, malnutrition an diabetes. Other possibilities include: